NEW YORK (Reuters Health) - Common variants in a gene
called LRP5 affect bone density and the risk of developing the
brittle-bone disease osteoporosis, according to a new study.
However, the impact of these variants on risk is modest.

Previous research has identified genetic mutations in LRP5
(for LDL receptor-related proteins 5) that cause rare disorders
associated with changes in bone mineral density. Whether common
variants in the gene for LRP5 and, possibly LRP6, affect the
risk of osteoporosis was unclear, however.

To investigate, Dr. John P. A. Ioannidis, from the
University of Ioannina School of Medicine in Greece, and
colleagues analyzed data from 18 centers in Europe and North
America covering a total of 37,534 subjects. The investigators
measured the participants' bone density and collected
information on any fractures via questionnaires and medical
records.

Two particular variants of LRP5 were associated with
reduced bone density in the lower spine and hip, the team
reports in the Journal of the American Medical Association.

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Both genetic variants were also tied to an elevated risk of
fractures, the report indicates.

The risks did not change markedly after adjusting for age,
weight, height, menopausal status, and hormone therapy.

A variant of LRP6, by contrast, did not affect the risk of
fractures, the researchers report.

They point out that finding a single marker provides only a
small clue to the likelihood of developing osteoporosis, but
"identification of several such osteoporosis risk variants may
eventually help in improving clinical prediction."